Duration of positional nystagmus in patients with horizontal canal type of benign paroxysmal positional vertigo
Duration of positional nystagmus in patients with horizontal canal type of benign paroxysmal positional vertigo
复制标题
良性阵发性位置性眩晕水平管型患者的位置性眼震持续时间
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
T. Imai
中科院分区：
文献类型：
--
作者：
T. Imai
most common cause of direction-changing positional nystagmus. H-BPPV with geotropic positional nystagmus is caused by canalolithiasis in the horizontal semicircular canal (HSCC). When a patient with HSCC canalolithiasis makes a lateral head turn toward the affected ear, the free-floating debris creates an ampullopetal endolymph flow. As a result, a geotropic nystagmus (fast phase toward the ground) is caused. When the patient turns away from the affected side, the free-floating debris creates an ampullofugal flow. The flow ends when the debris reaches its lowest position in the canal and the geotropic nystagmus disappears rapidly. On the other hand, some cases show geotropic positional nystagmus, which is not transient but persistent. Persistent geotropic positional nystagmus is induced by a light cupula. In this study, to classify these types of geotropic positional nystagmus as transient (transient geotropic positional nystagmus, TGPN) or persistent (persistent geotropic positional nystagmus, PGPN), the time constant (TC) of nystagmus was calculated. Geotropic positional nystagmus was recorded by video-oculography and analyzed threedimensionally. The slow phase eye velocity of nystagmus against time was approximated exponentially and TC was calculated as the reciprocal of the coefficient of time. Instances of geotropic positional nystagmus in patients with H-BPPV were classified as TGPN with a TC of <―35 sec or PGPN with a TC of >35 sec. In conclusion, we showed that the TC of positional nystagmus is an objective index of TGPN or PGPN and proposed that a TC of <― 35 sec indicates a TGPN while a TC of >35 sec indicates a PGPN. パネルディスカッション「外側半規管型良性発作性頭位めまい症」
影响因子：
2.5
作者：
Raphan, T
通讯作者：
Raphan, T